Binders are widely used to modify the interfacial characteristics and improve the ballability of iron ore particles. Funa is a natural polymer binder. It was developed and used in the production of iron ore pellets in China. In this paper, the interfacial interactions between Funa and a magnetite concentrate were investigated by measurements of surface tension, contact angle, wetting heat, zeta potential as well as by Infrared Spectroscopy (IRS) analysis as compared to bentonite binder. Results show that Funa behaves like surfactants and possesses the characteristics of colloid particles. It decreases the surface tension of water from 73 to 65 dyn cm(-1). The binder reduces the contact angle of the concentrate sharply from 46 to 0 at a dosage of 0.6% and hence greatly improves the hydrophilic character of the concentrate. Zeta potential measurements show that the surface of the magnetite concentrate is negatively charged and the addition of Funa causes more negative surface charges. IRS analysis shows that the binder adheres to the concentrate surface by chemical adsorption. It was also shown that bentonite has little effects on the surface tension, contact angle, wettability and Zeta potential. No chemical adsorption of bentonite on the concentrate was observed. (C) 2003 Elsevier B.V All rights reserved.